Furnace for the incineration of household refuse



Feb. 2, 1937. R L T N 2,069,584

FURNACE FOR THE INCINERATION OF HOUSEHOLD REFUSE Filed Jan..26, 1933 Ferr Lloffon Patented Feb. 2, 1937 2,069,584

STATES PATENT OFFICE FURNACE FOR THE INCINERATION OF HOUSEHOLD REFUSE Pierre Lorton, Paris, France Application January 26, 1933, Serial No. 653,737 In France January 29, 1932 Claims. (01. 110-13) The object of the present invention is a certain 8. On the pro-heating of the injected air by number of improvements in rotary hearth furthe clinker which remains at the bottom of the naces with a view to making said furnaces suitclinkering hopper, in order to keep the ash-pit able for the incineration of household refuse, a air at a given temperature (250 to 300 C.), the

5 further object of said improvements being to metallic parts of the rotating hearth being pre- 5 make it possible to keep said furnaces in continuserved from contact with theclinker and cooled ous operation whereas the present furnaces for by the air injection owing to the shape of the the incineration of household refuse only operate ash-hopper, thus ensuring their preservation; intermittently. 9. On the provision of a crushing device posi- Further these improvements procure, for the tioned beneath the clinkering hopper and in- 10 furnaces to which they are applied, a greater retended for the purpose of crushing the clinker;

sistance against the effects of the heat to which 10. On the provision of a screen positioned they are subjected. below the crushing device mentioned in 9; said These improvements bear: screen being intended for the purpose of arrest- 1. On the feeding of the substances which, acing any metallic substances which may be con- 15 cording to the invention, is effected in the center tained in the clinker and which may comprise of the furnace, said substances being made to a magnetic separation device or not; drop onto a trimming cone; 11. On the providing of a pneumatic conveyor 2. On a device for the regular distribution of starting from under the screen referred to in 10 the substances on the rotating hearth by means the purpose of which is to remove the crushed 20 of which the feed hopper does not tip the subashes to the storage or sorting installations. stances directly into the furnace but does so onto The attached drawing shows, as an instance, a distributor (a rotating plate distributor for how a furnace constructed according to the ininstance) which causes the substances to drop vention may be set up. evenly over the whole of the outer circumference Attempts have already been made, but With- 25 of the hearth; out success, to employ rotary hearth furnaces as 3. On the construction of the trimming cone incineration furnaces for household refuse. Such made in one piece with thin walls and provided furnaces were fed from the side and the subwith small blades intended to stir the substances, stances fell on the periphery of the bars thus the d a draught p p p g out inside said making it necessary (in order to insure even dis-v Q cone; tribution of the substances) to keep the hearth 4. On the providing of a crown, made of 'a in rotation while the furnme was being fed. As fireproof substance, on a level With e fi eox it is this rotation which regulates the evacuation and at the base of the tank, the Outl e f which of the slag the result was an interdependence beis designed in Such a manner as gradually etween the feeding and the evacuation of the slag 35 crease the surface of flow of the burnt substances hi h u ed th functioning of the furnace to and to retain said substances until combustion is be very irregular on account of the very h t complete; geneous composition of the substances inciner- 5. On the arrangement of the feed and clinkr a,

40 rin pp h axis of which is positioned The furnace which forms the subject matter of 40 di o the Vertical line passing through the the present invention obviates this disadvantage center of the hearth; by means of the central feed which can be effect- 6. On the provision o openings round the ed without the hearth being in rotation thus affeed hwper for the maniPulatmn of the fording the fullest freedom for the regulation of stances in Course of combustion; the rotation of the hearth according to the rate 7. On the constitution, in alignment with the fire-box and the ash-pit of a strengthening frame supporting the furnace body and made up of steel or reinforce-d concrete standards placed of combustion and the necessity of evacuating the slag. Continuous operation of the furnace and automatic evacuation of the slag are thus outside the walls in order that they may not be ensured" 50 subjected to the action of the heat of the furnace; on other hand furPaces of the tYPes at the wall which is thus placed inside of the present 111 1158 av t e disadvantage of placing strengthening parts is composed of sheet metal the essential components as well as the reinforceof a thin filling of reinforced concrete; it is lined m t members of the furnace 1 c t W h the with fireproof substance; fire. The furnace which forms the sub ect matter of the present invention remedies this disad- 7 base of the container, in line with the fire-box,

and by making the bottom of theoven of a special part composed of fireproof material the outline of which is designed in such'a manner as to provide a passage of progressively reduced section for the substances in course of combustion and for the clinker, thus ensuring a good combustion as well as automatic removal of the clinker and good preservation of the furnace.

The hearths of furnaces which are capable of being made suitable for the incineration of household refuse are generally composed of two metallic cones I and'2, having dissimilar summit angles, on which the substancesit is desired to burn are placed. Up to the present the upper cone, into which the injected air arrives,:'was made of thick cast iron sections assembled by means of bolts. It was noticed however that a cone, constructed in this manner; deteriorated very rapidly and that, in addition, the various sections, being subject to dissimilar degrees of expansion, caused openings to be formed throu h which the injected air passed direct in the form of jets instead of passing under the fire-bars. 7

One of the improvements which constitute the invention consists in making cone2 from thin metal and in one single piece as said cone is not f submitted to any mechanical efforts; the petitioner has, in fact, noticed that cones 2made of thin metal resisted in a perfect manner against the destructive action of the substances under treatment and of fire.

In the furnaces of the type at present in use furnace was subject to distorsion likely to result in dislocation and corrosion was very rapid; according to the invention the carcase of the ash tray is made up of metallic'parts or of reinforced concrete positioned outside the wall which forms the base of the container and of, the ash-tray. Said wall is itself constituted by sheet metal or a filling 4 made of reinforced concrete; a lining 5 made with fire-proof material is positioned inside against the wall.

According to the invention, between the combustion container and the base of the furnace, a crown 6 made up of fireproof components suitably shaped in order to narrow down the evacuation section and ensure complete combustion, has been provided. This arrangement does away with the metallic crown usually applied in rotating hearth furnaces of the types at presentknown; the fire-proof crown resists perfectly against the destructive effects of the fire, a result it was not possible to obtain with the metallic crowns.

The raw material for the furnace is-fed by a hopper 'I positioned at the upper part of the apparatus and according to its axis. This hopper comprises a prismatic or conical portion 8 which is followed by a cylindrical-conical part 9 terminating at the bottom in-a conical portion I0.

Portion 8 of the hopper is closed, at its lower part, by a mitre plug I I, the downward movement of said plug which determines the opening of the hearth of the furnace.

the piassage is procured by actuating operating rod V When mitre-plug I I is open the material drops into distributor I8 which may be of any suitable model, that shown on the drawing being given merely as an example.

In the form of embodiment shown the distributor comprises a plate I9 rotating on an annular 2I and, on its upper surface with teeth 22 which, when said plate is rotating move between other teeth 23 solid with casing 9 in which the distributor assembly is housed.

The rotation of plate I9 determines a slow angular displacement of opening 2| through which the substances stirred by the combined system of teeth 22 and 23 drop through passage 25 onto The distribution of the substances over the whole surface" of the rotating hearth is thus insured owing to the angular displacement of opening 2|.

The material which drops from the hearth collects in the emptying hopper I3 which is positioned according to the general axis of the furnace and which is provided, at the bottom, with an opening IL The walls of this hopper are constituted by an outer revetment of sheet metal or reinforced concrete and they are coated inside with a fire-proof lining I6.

The sealing of opening I4 is obtained by means of two crusher cylinders 21 and 28 rotating at low speed and between which the clinker is crushed.

The clinker which is in a state of ignition can be allowed to remain for a certain length of time at the base of container I3 thus heating up the air injected through tubing I5 to a temperature comprised between 250 and 300 C. a

After having been crushed the ashes drop onto an inclined screen 29 which arrests, on its upper surface, those metallic portions contained in said ashes the size of which hasremained greater than V the spaces between the bars of the screen.

Moreover a magnetic separator may be combined with screen 29 in order to arrest the metallic elements which drop onto it with greater certainty. The non-metallic substances pass through the screen and dropto the lower portion of box 30 whence they are removed, either continuously or not, and are conveyed to apparatus intended to treat them in a special manner, to storage bins or to any other location previously selected;

the removal of said ashes is by means ofsuction,

pipes 3I since pneumatic handling is possible owing to the fact that the clinker being crushed while hot it is in a sufficiently perfect pulverous state to permit of this system of handling.

In a furnace constructed in the manner indicated above the feeding of the substances to be incinerated and the removal of the clinker can be effected at varying intervals according to the nature of the refuse under treatment; basis I! of the hearth is capable of angular displacement and it is caused to rotate, from time to time, by any suitable means in order to cause the removal of the clinker by making the ashes drop from the base of said hearth.

Continuous operation of the furnace is thus obtained and this had not been previously attained, all furnaces for the incineration of household refuse working intermittently on account of the necessity of suspending operation for the purpose of removing the resulting clinker from the hearth.

What is claimed is:

1. Ahousehold refuse-incinerator comprising in combination, a hopper for feeding the substances to be incinerated, a distributor positioned below said hopper and above the center of the combustion chamber, a rotatable hearth, said distributor including means for distributing said substances over the upper surface of said hearth, said hearth having a central agitating cone made of one single piece of thin metal and provided with stiring blades, means for introducing air within said cone, means for causing said hearth to rotate, a receiving hopper below said hearth having downwardly converging side walls for evacuating the clinker, rotatable crushing rollers at the bottom of said receiving hopper, a screen below said rollers for arresting the passage of metallic substances and suction means below said screen for evacuating the pulverized clinker.

2. In a. household refuse incinerator according to claim 1, wherein said feeding hopper gradually decreases in cross section downwardly.

3. In a household refuse incinerator according to claim 1, wherein means are provided utilizing the clinker heat effect upon said means for introducing air for heating the air blown into the central agitating cone.

4. In a household refuse incinerator according to claim 1 wherein the feeding and receiving hoppers are positioned so that the axes thereof coincide with a vertical line drawn through the center of the hearth.

5. In a household refuse incinerator according to claim 1 wherein there is provided in alignment with the fire-box and the ash-pit, a reinforcing framework positioned outside the furnace walls.

PIERRE LORTON. 

